South African wine has a history dating back to 1659, with the first bottle produced in Cape Town by its founder Jan van Riebeeck. There are about 60 appellations within the Wine of Origin (WO) system, which was implemented in 1973 with a hierarchy of designated production regions, districts and wards. WO wines must only contain grapes from the specific area of origin. "Single vineyard" wines must come from a defined area of less than 6 hectares. An "Estate Wine" can come from adjacent farms if they are farmed together and wine is produced on site. A ward is an area with a distinctive soil type or climate and is roughly equivalent to a European appellation.